Therefore: ∠ ABC+∠ bad = 180.
Because AB = 5, AC = 9, ∠ BCA = 30 and AB/sin∠BCA=AC/sin∠ABC.
Therefore: sin∠ABC=9/ 10.
Therefore: sin∠BAD=sin∠ABC=9/ 10.
And: AB/sin∠ADB =BD/sin∠BAD, ∠ ADB = 45.
Therefore: BD=9√2/2.
1. What about Huaying Education in Tianjin?
The school adheres to the mode of "one main line (education and teaching) and